1921] NATURAL SCIENCES OF PHILADELPHIA. 149 



distinguishing characters, of much greater importance: the layer 

 of starch grains which hes upon the inner surface of the chromato- 

 phores in Crypiomonas ovata was quite absent in Cr. curvata, and 

 the same relations obtained in the case of the two big crystalloid 

 bodies, which never are present in these species; besides, a curious 

 fact was seen in curvata: if from the bases of the flagella their line 

 of direction was followed downwards, as far as the middle of the 

 pharyngeal pit, one invariably found there a special granule, very 

 distinct after compression of the animalcule, of a pale bluish hue, 

 and which immediately reddened with borax-carmine, a kineto- 

 nucleus, very probably, which could not be detected in Cr. ovata. 



After these considerations of a systematic nature, I come now 

 back to phenomena which proved common to both species, and 

 which, indeed, were the only inducement to my observing Crypto- 

 monas at some length: I mean those sudden leaps or jumps, which 

 have long been known in the genus, and those explanation has 

 never been given, or at any rate has not been proved. 



From time to time, without any apparent reason or on account 

 of some discernible danger, the animalcule suddenly leaps back- 

 ward, in an amazing jump, five, ten, twenty times its own length, 

 describing an arc or even a nearly complete circle, and always to- 

 ward the same side, its ventral or concave side facing towards the 

 center of the described arc. When danger grows extreme, and the 

 irritation is at its greatest, the jumps succeed each other without 

 intermission for a few seconds, and at last the little Flagellate falls 

 down exhausted, or sometimes bursts altogether, as if some inside 

 rupture of equilibrium has been produced, which dislocates its 

 different constituents, leaving the animalcule as a shapeless body, 

 with nucleus, starch grains, chromatophores, etc., scattered here 

 and there. 



Where are we to find the cause of these sudden jerks, the organ 

 that might produce them? The flagella are out of the question; 

 they are too weak, and besides, those individuals that happen to 

 be deprived of flagella jump just as well as the others. Ehrenberg 

 looks for the explanation in a contraction of the "lateral trunk" 

 the beak -like prolongation, if indeed such is the meaning of the only 

 line he devotes to the subject: "Das rasche Anstossen des seithchen 

 Riissels veranlasste offenbar das Hiipfen." But neither beak nor 

 trunk are in the least degree susceptible of any displacement. An- 

 other explanation has been proposed, to which Pascher ("Siiss- 



